Prepping Fiberglass Parts for Paint

I've got to admit, working with fiberglass doesn't top my list of favorite autobody repair chores – especially in an environment that's as hot as it is here in Southern California. I always feel as though I'd been mugged by an irate itching powder salesman by the time my forays into 'glass repairs are barely completed. But, luckily the majority of fiberglass bodies and accessories are top-quality these days and don't require much in the way of major reworking like they did years ago. However, there are still times when they need a bit of extra prep work to make 'em perfect.

Speaking of making things perfect, a recent trip to Uncle Bitchin's shop offered me and my pal Rob Fortier (the only one with a camera at the time) a textbook case in point. Butch "Uncle Bitchin" Lynch just happened to be in the process of massaging a couple of huge 'glass Cameo bedsides. In Butch's opinion anyway, the panel's bodylines were good, but not perfect – and with Butch, things have to be done perfectly or not at all. That said, we hung out to watch and learn how a professional goes about transforming good 'glass to perfect 'glass.

2/361. As is the case with any automotive chore, bodywork and paint prep requires specialized tools – most importantly, sanding blocks. Today, you have a wide variety of styles and shapes to choose from…just be sure you use the right one for the job!

3/362. And, just like the specialized tools one needs for doing good bodywork and paint prep, the materials like filler, glazing compound, and primers should be chosen carefully, as well. Stay away from the automotive aisle at the dime store and use high-quality material for your repairs. That 10-gallon of no-name filler will cost you more in the end, believe me.

4/363. Our test subject for the day's lesson is a nice little 1955 Cameo currently undergoing the Full Monty at Uncle Bitchin's in Temecula, California.

5/364. Despite an honest effort, the truck's previous bodywork wasn't quite up to par, which just compounded the to-do list for Butch "Uncle Bitchin" Lynch and his multi-talented sidekick, his daughter Kelsey. First order of duty: bodylines (or more precisely, straightening them).

6/365. Masking tape is pulled and scribe lines drawn (often in conjunction with a long straightedge) along the Cameo's less-than-straight and defined bodylines, all of which will be used for sanding references.

7/366. The bedside's spine is very eye-catching – and so too is its unevenness, a flaw in the fiberglass panels straight from the GM factory some 50-plus years ago. No reason it needs to stay that way though.

8/367. This shows how uneven the side of the truck is.

9/368. The side reveals on the bed, which are just as wavy and uneven, if not worse. Legend has it that the Cameo project didn't quite get the factory attention the Corvettes did, and after seeing this one's bed, we believe it!

10/369. The taillight, which is an original item, as there are no aftermarket reproductions that we're aware of, serves as a bodyline vantage point reference, despite the fact that it's about as straight as the bedsides. Unfortunately, it can't be altered, so the adjustments will have to be made around it.

11/3610. Just to give you a quick idea of how the scribe lines are used, Butch takes a short block and begins sanding the surface in question down until it gets closer and more uniform with the line.

12/3611. Here's what the panel looks like as it nears the scribe line.

13/3612. In essence, to avoid making waves (or more of them in this case), use longer sanding blocks on larger panels or areas, as Kelsey is shown doing here. But, because of the multi-contoured shape of the area she's working on, she's careful not to get carried away and gouge the recess below the block. Masking tape can help prevent this, too.

14/3613. The easiest thing for a beginner to do when block sanding is to get too aggressive. Along with getting the

15/3614. Without exaggeration, the taillight was put on and taken off more times in one day than it had in its entire lifetime. Why? To avoid sanding too much material off, that's why.

16/3615. As you can see, the spine is starting to take shape, literally.

17/3616. Along with physical reference points, another good way to gauge progress is with a method called "guide coating', which is simply contrasting color fogged over the surface. Lightly sanding will reveal high and low spots.

18/3617. Butch also re-scribes vital areas over a fresh guide coat just to keep everything in line, so to speak.

19/3618. Generally, work body filler (or even fiberglass) down in grit succession. In other words, start rough with 36-grit to knock down initially, then gradually work finer (80, 120, 320, etc.) to avoid sanding too much or leave sanding marks.

20/3619. Once you get fairly close, STOP! It can't be stressed enough how important it is not to sand too much. At this point, the bedside's spine will be left alone while other areas are focused on.

21/3620. With the taillight remounted for the umpteenth time, a straight edge shows the variance between the quarter panel and the exterior of the taillight bezel – about 3⁄8-inch gap, which needs to be addressed.

22/3621. To compensate, Butch and Kelsey will bridge the gap with polyester body filler. At first, most people make too large of a batch – and often, slap too much material on, all in all creating more waste than usable filler. Practice will perfect the batch making process.

23/3622. Anywhere you don't want the body filler, make sure you cover appropriately (with masking tape). That includes existing bodylines, as you see Butch has separated the upper and lower sections of the bed.

24/3623. Once the filler has just started to set up (harden), quickly knock down the high excess material, but don't wait too long, as fully hardened filler is a lot "harder" to sand. On the initial spread, you'll probably have a low spot or two, as shown here – just add more.

25/3624. As mentioned earlier, you will notice a huge difference in both application and workability between cheap body filler and name-brand lightweight filler. Quality products go a long way in ensuring quality results.

26/3625. A good trick for sanding is to use a wooden paint paddle (free at most paint supply stores) as a sanding block.

27/3626. Using adhesive-backed sandpaper, Butch makes good use of these little paddles. Notice the way the different-colored areas fade or blend into each other – this is an example of "feather edging."

28/3627. Once the sides of the bed were knocked out, the taillight-mounting surface itself needed a little leveling as well.

29/3628. The same paint paddle used for sanding shows how flush the taillight bezel will now sit thanks to some attention given to the back end of the bedside.

30/3629. Lengthwise, the panel is definitely shaping up nicely...but despite what the straightedge shows here, there's still more work to be done.

31/3630. With a red fine-tip marker, Butch traces the outline of the taillight bezel along the mounting surface. The side of the bed will need to be sanded down enough to make that line disappear.

32/3631. Finally, with all the panels and edges smooth and straight, the newly sharp edges are lightly knocked down and given a nice, soft, rounded edge.

33/3632. With the bedside "roughed" in (flat and aligned, but still needing some hours of blocking), Butch lays down a few coats of primer.

34/3633. Here is the untouched bedside.

35/3634. Compare the freshly bodyworked side to the uneven side – big difference.

36/3635. Though there's still plenty of work to be done before any real paint can be applied, at least straight and uniform bodylines have been established, leaving only the tedious chore of further block-sanding the large flat areas, but that's just one side of the bed…there's still the rest of the truck to go!